Crude oil recovery can include several stages. During the primary recovery stage, the natural pressure of the reservoir drives oil into the wellbore and up to the surface. As the reservoir pressure declines because of production, an artificial lift system is normally implemented. Production using artificial lift is also considered primary recovery. When primary recovery stage reaches its limit, water or gas can be injected to displace oil and drive it to a production wellbore during secondary or tertiary recovery.
During any stage of reservoir production, enhanced oil recovery (EOR) techniques can be used to increase the amount of crude oil that can be extracted from the reservoir. There are several techniques for EOR—chemical injection is one of them. Chemical techniques inject surfactants (surfactant flooding) to reduce the interfacial tension that prevents or inhibits oil droplets from moving through a reservoir or inject polymers that allow the oil present in the formation to more easily mobilize through the formation.
Chemical EOR requires optimization for maximum effect. The optimal selection of surfactants and/or polymers depends on reservoir crude oil chemistry, temperature, pressure, permeability, residual oil composition, fluid properties and the like. Traditional methods to evaluate the effectiveness of chemicals to enhance oil production include sand pack and core flood tests. While these methods are beneficial testing tools, they can be labor intensive and time consuming. Accordingly, the art would be receptive to alternative methods that are effective to rapidly screening chemicals to enhance oil recovery.